Row crops are routinely cultivated one or more times during the growing season. As the soil is turned by the cultivator shovels, however, it may damage the crop, particularly if the crop is young and tender. Consequently, shields of various types have been devised to protect the crop from damage by dirt being thrown by cultivator shovels.
One type of shield employed is the rolling or rotating shield. Such shield, typified by U.S. Pat. No. 3,429,379, consists essentially of a disk-shaped member, often concave, carried adjacent the outer-most shovel in a multiple shovel gang (i.e., a gang having multiple shovels in each row). Any dirt being thrown by the adjacent shovel strikes the shield rather than the crop.
For wide row crops and larger size crops, the above rolling shield technique has proven adequate. For precision cultivation of crops in narrower rows (e.g., about 22 inches, as is commonly used for sugar beets and other crops), however, such rolling shields do not provide adequate protection from dirt being thrown from even shovels located in the center of the row. To achieve greater protection for such crops, particularly when they are young and tender, farmers have used tunnel shields. Tunnel shields consist essentially of an inverted trough that extends along a row, covering the crop along the entire length of the cultivator.
Tunnel shields, however, introduce additional problems, in that they easily clog with trash left in the field. To avoid damage to the crop, the tunnels must be manually cleaned whenever they become clogged. This problem has become more acute as farmers seek to farm with increased crop residue in order to reduce soil erosion and conserve water. Moreover, in particularly mellow ground the tunnel shields, being suspended from the cultivator frame, do not always protect the plants from being covered by soil, limiting the speed at which the cultivator may be pulled.